Color photographic process



Patented Feb. 4, 1941 coLoa rnorocnarmc PROCESS John Eggert, Leipzig, and Gen! Heymer, Wolfen, Kreis Bitteri'eld, Germany, assignors, by mesne assignments, to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Y Application December 30, 1938, Sc-f rial No. 248,520. In Germany January 22, i938 1 Claim. (Cl. 95-2) The present invention relates to a color photographic printing process.

In the production of multi-color photographic prints it has been proposed to employ a multi- 5 layer photographic material which carries on one side of the support a silver halide emulsion layer provided with a yellow filter dyestufi; after exposure and development this layer is converted by a toning process into an ironbluepicture; on the other side of the support there are superimposed on'e upon the other a yellow colored layer and a purple colored layer which are sensitized for difierent regions of the spectrum, in sucha manner that the sensitivity regions do not coincide with the absorptionregions so that the lower layer obtains the light necessary for exposure through the superimposed layer. For example, the purple layer may be sensitive, to red light which is permitted to pass through the superimposed yellow layer sensitized to green light. Such a material must be so exposed that the green component is copied by means of red light in the purple layer and the blue component by means of green light in the yellow layer. Correspondingly, the red component is copied by means of blue light in the singlelayer on the other side of the support. For printing on a film of this kind the usual black-and-white color separation pictures which, if desired,-may be combined on a lenticular screen film, may be employed. The Production of the color separation pictures by means of such material has, however, several disadvantages. Forexample, for producing the ordinary black-and-white cornponents special exposure apparatus is necessary,

while exposure on lenticular screen films produces pictures which lack in definition of the color values far removed from the objective.

These disadvantages have been avoided in the 40 modem multi-layer films in which the color pic-' tures are produced by color 'tormingdevelopment. In this case a-color picture can be produced in various ways, for instance, with the' aid of controlled-.gliiiusion in the color forming development or by addition of the dyestufi components to the several layers during the .fllm production, and later development'with the aid of a single developer. These latter can be developed by a simple development to a negative and by reversaldevelopment directly to a positive.- The present invention is based on the observation that for the production of multi-color pic-' tures it is of especial advantage to use for the exposure a multi-layer photographic material yields pictures of full color.

having silver halide emulsion layers of dificrent sensitivities in whichthe colored picture is pro-- ducedhy color forming development and to use as a printing material a multi-Iayenphotographm element in which in a part of the layers a picture and in the rest by. the toning method. This combination of exposure and printing processes is the more satisfactory because the exposure utilizes'only a single film and therefore only an ordinary camera and'because the copying process It is thus possible to produce the sound track as an iron-blue image which 'is'more impermeable for the infra-red rays corresponding with the sensitivity of the sound film photocell than are the dyestufis normally used in color forming development. When producing the master picture in the usual manner,

-is produced by the silver bleaching-out process is subjected to reversal color forming development, but with the essential deviation that the.

dyestufi components areso interchanged in their relationship in the several layers that the color in the blue-sensitive' exposure layer is complein which the yellow layer is green-sensitive, the

purple layer is red-sensitive and the third layer, intended for the bluetone, is in general sensitive to blue, the relationship of the color formers to the several layers in the master picture film is as follows:

p 1. Blue-sensitive layer which on account of the green sensitivity of the yellow layer is provided with a dyestuff component for purple;

2. Green-sensitive layer which is provided with a dyestufl component for blue-green;

3. Red-sensitive layer which is provided with a dyestufl component'ior yellow. V

The color picture isgproduced by reversal development, the first development by means of a black-andgwhite developer while only in they second development 'a developer is used which produces a color picture in the three layers. The color developed film naturally presents a: peculiar interchange of the colors. This material is, ac-

cording to'the invention, copied on the abovedescribed multi-layer copying material in the following manner:

From the third layer of the exposure film the red component is copied with the aid of a blue filter on a black-and-white film which is developed to a negative; the latter is now copied in the usual manner on that layer of the copying material in which the picture is produced by iron-blue toning. On the two other layers of the copying film the original itself is copied, the film being copied either successively first with a red filter and then with a green filter or the reverse or simultaneously with a yellow filter which contains the necessary colors red and green. Furthermore, the operation may be performed with a copying apparatus which contains side by side a red and a yellow filter which has the advantage that the copying light for the two component colors can be better adapted by. varying the passage of light by means of diaphragms. Both for the exposure film and for theoopying film regions of spectral sensitivity may be used other than those given in the above example. correspondingly, the colors of the copy ing light must then be changed while at the same time the color formers of the exposure film must be so varied that they are again complementary to the copying filters.

For the master picture film layers are particin the U. S. patent applications Ser. Nos. 90,726,

filed July 15, 1936, now-Patent No. 2,178,612 of Nov. 7, 1939; 158,860 filed August 13, 1937, now Patent No. 2,179,244 of Nov. 7, 1939; 159,518 filed August 17, 1937, now PatentNo. 2,186,732 of January 9, 1940; 164,499 filed September 18, 1937, now Patent No. 2,186,733 of January 1940; 166,832 filed October 1, 1937, now Patent 2,186,851 of January 9, 1940; 171,701 filed October 29, 1937, now Patent No. 2,186,734 of January 9, 1940; 171,705 filed October 29, 1937, now Patent No. 2,186,735 of January 9, 1940; 175,285 filed November 18, 1937, now Patent No. 2,186,719 of January 9, 1940; 176,058 filed November 23, 1937, now Patent No. 2,186,852 oi January 9, 1940; 191,952 filed February 23, 1938.

Asaprintingmaterialafilmsuchasisdescribed in the British Patent No. 454.088 is especially suitable (see also 0. S. patent application Ber. No. 51,029 filed November 22, 1935, now Patent No. 2,205,755, of J1me 25, 1940).

A modificatiom of the arrangement of the color formers in 'the exposure printing fihn is as follows:

On the printing film the layer on the one side which is adapted to be toned blue remains'the same as in the modification described on pages 1 and 2. On the other side of the support'there is arranged a-yellow layer which is red-sensitive film and of the and on top of that a purple layer which is unsensitised and, therefore blue-sensitive. The corresponding exposure film has the following arrangement of layers:

1. Blue-sensitive layer containing color former 5 for blue-green,

2. Green-sensitive former for yellow,

3. Red-sensitive layer containing color former for purple, l0

4. Support.

After reversal development a negative red color separation is produced by means of a green filter. This red color separation is printed onto the layer adapted for blue-toning in the printing l5 film as before. The remaining layers of the exposure film are printed onto the two colored layers of the printing material in exactly the same manner as in the example previously described the only difierence being that blue and 20 red filters are employed respectively.

We claim: v

A process of producing colored photographic prints in a photographic multi-layer printing material in which one layer is a colorless emul- 2 layer containing color sion, another layer is a green sensitive emulsion containing a yellow dyestufi which is fast to ordinary photographic baths but is capable of be- -ing. destroyed by reaction at the silver image 'of being destroyed by reaction at the silver image portions which comprises exposing to a colored object a color photographic multi-layer film 35 containing in each layer a color forming development component fast to difiusion arranged as follows: a color-forming development component for purple being arranged in the blue-sensitive layer, a color forming development com- 4,) ponent for blue-green in the green-sensitive layer, a color forming development component for yellow in the red-sensitive layer, developing said film first with a black-and-white developer and then with a color forming developer to a 5 reversal picture, printing a color separation negative from said red-sensitive layer onto an ordinary black-and-white film, copying said negative onto the colorless layer of said photomphic multi-iayer printing material, copying the blue sensitive layer onto the layer of said photographic multi-layer printing material containing the yollow dyestuif, copying the green sensitive layer onto the layer of said photographic multi-layer printing material containing the magenta dyestufi, developing said printlug-material, toning said colorless layer blue and destroying the dyestuifs at the silver image portions of the yellow and magenta layers by the sllver-dye-bleaching-out process. JOHN EGGERT.

GERD HEYMER. 

